1. Field of the Invention
The present invention relates to a method and a corresponding apparatus and system for automated labeling of a spine in an image, in particular a computed tomography (CT) image, of a human or animal body.
2. Description of the Related Art
The acquisition of CT images with and without contrast agent of abdomen, thorax and/or neck is a routine procedure for the diagnosis of a multitude of diseases or injuries. The spinal column represents a natural reference structure of the upper part of the body for describing the locations of organs and pathologies. To be used as a reference system in daily clinical routine, the vertebrae and/or intervertebral disks in the image have to be labeled. A manual labeling can be time consuming, especially if only arbitrary parts of the spine are visible in the data. Therefore, automatic approaches are of interest which deliver labeling results after image acquisition without any user interaction.
For the labeling task, a sparse localization of spine components, e.g. vertebrae and/or disks, is sufficient. Within this context, the term “sparse” refers to the requirement according to which correct anatomical labels should be visible in all views showing a certain vertebra or intervertebral disk, and optionally also in a 3D rendering. This does not necessarily require a full segmentation of all spinal structures. The localization of centers of disks and vertebrae and a coarse approximation of their extent delivers adequate results.
Although this task seems to be trivial, the realization of a fully automatic labeling system for 3D CT data supporting radiologists is challenging: The labeling should be available within a reasonable time in order to guarantee a fast diagnosis after image acquisition. Nonetheless, the labeling algorithm has to reliably handle varying resolution and image quality, showing spinal columns with variations in size, shape, bone densities and varying number of vertebrae. Presence of contrast agent or pathologies like scoliosis, collapsed disks, broken vertebrae, degenerative changes or fused vertebrae based on surgical procedures make high demands on the flexibility of the chosen methods.